Handheld electronic devices, such as tablets and smartphones, are widely used in the world at the present time. Such handheld electronic devices are now capable of performing most of the same functions as a laptop or desktop computer, and as such, the software they execute is growing in complexity. In addition, most such devices utilize a touch sensitive screen as the main input device, and the software currently employed may utilize complex gestures made on the screen, in addition to taps and swipes, as input commands.
Since accuracy in recognizing these inputs is desirable, it is helpful to maximize the dynamic range and sensitivity of the touch sensitive screens. To this end, it is useful to discharge the parasitic capacitances in the circuitry of the touch sensitive screens. While methods of discharging such parasitic capacitances are known, such methods involve the use of transistors that source current, and thus suffer from the flicker noise inherent to transistors performing that function.
Therefore, new methods of discharging the parasitic capacitances of touch screens are desired.